This invention relates to a musical key determining device which determines a musical key of a music piece on the basis of chord and melody data of the piece.
For application in automatic accompaniment and arrangement of a music piece, various devices are proposed which serve to determine a key of the music piece on the basis of actually performed contents (automatic performance data). For example, U.S. Pat. No. 5,056,401 discloses such a device that determines a key of a music piece on the basis of detection of a specific chord progression. But, the disclosed musical key determining device requires a very complex structure, since it determines a key by covering or tracing a very complicated progression of chords. In addition, because the same kind of chord progression is used for various different keys, it is not always possible to determine a specific key only by tracing a chord progression. In such a case, a specific key determined from among various different keys, very often, tends to be incorrect, and therefore the determined key can not be used for automatic accompaniment and/or automatic arrangement. Besides, in some cases, such a key is determined which corresponds to the chord progression but not to the melody.